I just started riding longer distances to improve my balance skills.
I rode 2 miles yesterday and then 4 today. After my ride yesterday, I noticed that while moving my muni around to put it away, it sounded “glunky” so I jiggled stuff and bounced it up & down and noticed the bearing retainer bolts had become loose from my frame.
Okay? So I snugged them back up to snug but not impeding the crank spin very much(felt free).
So then I go out riding today(both times paved hilly but easy pedestrian trails) and during the ride I had to snug them up again. Now when I put the uni away, again I noticed a bit of looseness in the bolts but it wasn’t bad enough to hear or cause wobble.
Am I not tightening them enough to start with? They are snug but not like wrench imprint in your hand snug. I worry about too tight and ruining my bearings but obviously I don’t want to cause an unsafe situation.
I don’t have anything here that can tell me how many ftlbs or any gauge of torque. Should I take it to my LBS? Do you tighten until the cranks slow down noticeably?
I haven’t had any other issues.
I have a Surly Conundrum 24" I got used(a bike shop owner who never learned to ride it more than 30ft). Has KH moment hub and 150mm cranks. V8 pedals and Large Marge rim.
Use blue loctite. Tighten first bearing cap and spin wheel. Back off bolts until the wheel spins semi-freely, but takes longer to slow down. Repeat with second cap.
Lock Nuts on KH bearing cups
I found this old thread on an issue that doesn’t seem to be discussed that much considering how annoying it is. Although there is plenty of discussion on how tight to turn the bearing cup bolts which I have digested and experimented with over a couple of years of loving KH muni ownership, only Loctite has been suggested to prevent the inevitable loosening of the bolts over 10 or 20 kilometres or so. (Unless there’s a thread on the blog that I didn’t find). The split washers that come standard don’t seem to do much to prevent loosening.
For the last few months I have had blue Loctite in the threads and this slows the loosening to every 50 kilometres or so but makes removing and replacing the bolts somewhat of a trial. It also gives enough resistance to turning of the bolts that you lose the feel of how tight you are snugging them up.
Now there’s no way my understanding or experience of a unicycle would come anywhere near to that of Kris Holm. But over the months I have not been able to put out of my mind the idea that bolts with locknuts would solve this problem. So eventually I decided this was an experiment that I had to undertake for my own satisfaction.
So, I cleaned out as much of the Loctite as possible with Loctite Glue Remover and acetone. I bought some 6mm x 25mm metric stainless steel bolts that protrude on the topside and some Nylex style locknuts (for their rounded profile). No washers or split washers. I tightened the bolts up just enough to stop the bearings moving around. There was nice free rotation of the wheel. Then I tightened the locknuts up nice and tight. There was no alteration in the bearing cup tightness with tightening the locknuts.
Went for a ride. Developed some creaking after a few ks. I figured this was the residual Loctite in the threads or some dirt or paint flattening out. Tightened the bolts again. Did about 10 ks of muni yesterday and no creaking developed and the wheel still turns freely.
So this is my experiment, and if I post this today it will be a prospective trial. I’ll report progress every month or so. Main outcome measure: frequency of the need for tightening of the bearing cup bolts.
Here is a photo of the new bolts with locknuts.
Not sure if you need to do that on a KH frame. Unlike other unicycle types, where the two halves of the bearing holders don’t meet, you have to limit your tightening so it doesn’t put too much pressure on the bearings. But on a KH (or other types of machined bearing holders) the two halves are meant to press together. If this is the case with yours, it’s okay to crank them down nice and tight.
However if tightening the bolts a lot does cause the wheel to not spin freely, the locknut approach seems like a great idea. On lesser unicycles, with non-meeting bearing holders, locknuts have historically been a sensible upgrade. Those already had bolts that stuck out, so you only had to buy new nuts. It’s slightly more involved for unicycles like the KH where you also have to get some longer bolts.
I’ve only ever had this problem when I un-and-retighten the bolts (eg. to take the wheel off for puncture repairs). The first 2 rides work them loose, then after that they’re fine until the next puncture. This is on Qu-Ax, so pressed bearing holders and presumably cheap bolts. How do the stock KH bolts look when compared to the Qu-Ax ones…?
Blue Loctite usually works. If you don’t have blue loctite then you might try binding the bolt threads with some plumbers 'thread seal tape’which should tighten the bolt fit on the thread and help absorb vibration. 
I usually tighten the cup bolts and then loosen them until the wheel rotates 8/10 revolutions after a hand rotation before stopping. i.e. stand the uni on it’s saddle, grip the tyre and spin the wheel with your hand.
Hope this helps.
Is that true? Doesn’t that conflict with the Schlumpf hub instructions to only tighten to <5Nm? And once the caps are in contact with the frame, how will tightening any hard have any effect?
I’ve found this to be a problem in the past and ended up using a belt sander to remove the paint and perhaps a few microns of aluminum from the surfaces between the caps and frame. I could then tighten correctly (to my judgement), with a tiny gap, and I’ve never seen it as a problem.
Tools haven’t been mentioned here from my experience: If you don’t use a ratchet handle with a hex bit, they won’t be tight enough to stay. You can’t apply enough torque with a T-handle wrench or L-shaped Allen key to get a screw that size to self-lock. Mechanically impossible unless you’re strong enough to lift your entire body weight with a single finger.
An L-shaped allen key works fine on my KH and Nimbus uni’s. I must be reeaaaly strong. 
Whole body weight on a single finger??
If the goal is 5 Nm then it is easily achieved with an L hex wrench. 5 Nm is about 5 kg force at 100 mm. Clearly it is possible to do a lot more than this.
I have never measured the torque but I do use more than 5 Nm. I use a folding Allen key set. I have not had any problem with caps coming loose on either of my KH unicycles.
I have worked extensively with nuts and bolts from those inside clocks to those on a tractor since I was a kid and have a good feel for what is appropriate.
5 Newton-meters is pretty low. I wouldn’t be confident using that. And 100 mm is a pretty generous estimate for lever length unless your Allen wrenches are a lot longer than mine.
But it’s your stuff and you can do what you want with it, as long as it works for you. I’ll use my ratchet.
NOT SURE IF THAT IS TRUE! My only KH frame has a Schlumpf hub in it, so the rules are different than for normal axles. For Schlumpfs, it’s important to have sufficient, but not too much, pressure to keep the bearing from spinning.
The 5 Nm also applies to Schlumpf hubs, so not sure what’s appropriate for KH frames with ungeared hubs.
Most of my unicycles are older. When I ride any but my Wilder off-road, it’s usually all about tightening the (square taper) cranks. I just do it before every ride, and that seems to be sufficient.
FWIW, in my older KH36 frame with Schlumpf hub, there is a gap between the caps. Not much, but it’s there. Yes, 5nM is pretty light, the first time I installed the hub using the torque wrench I was surprised at how light it was. After that I just used “light” finger-tight force when putting these together.
An update on my experiment putting locknuts on the bearing cup bolts on my KH26:
Creaking developed 3 times over 2 weeks and I tightened the bolts each time, after which the creaking stopped. This may have been loctite in the threads squishing down.
For the last 2 weeks no creaking has developed, no tightening of the bolts has been necessary. The wheel spins freely.
I may have solved bearing cup loosening on my KH26.
Let’s see what happens for the next month.
Locknuts have solved the issue. A month since my last post, riding muni 4 days a week (how did I get so lucky!). No adjustments to the bearing bolts have been necessary.
What I do is tighten them until snug then again 1/4 turn on left and right sides, sometimes alternating which nut on the bearing cap to keep it level untill wheel spin is effected, then back a quarter turn.
I had this loosening problem on a uni (so bad I had to tighten mid ride) so I got longer bolts, lock washer and locking nuts. Supposedly if you get locking nuts, locking washers is unnessesary but I’ve had them back out, especially if they’ve been done and undone multiple times.
Unis are notorious for parts getting loose so all of my unis I regularly check to make sure everything is tight. This happens more on some unis than others, on one it’s every ride that something (always something different) has gotten loose.
The only thing I ever had to tighten during a ride was my brake lever extension.